Rails: Re-using models, controllers and even views between Rails applications

I have a rails app which contains some fairly generic functionality (eg managing users). I would like to use that common functionality in other rails apps without copying it. The hard part seems to be that this code contains a num开发者_运维百科ber of models, controllers and views.

I know that gems and plug-ins allow code to be shared but they seem to apply more to sharing utility and library functionality rather than core parts of an app.

Any advice on how to do this would be greatly appreciated.

We are working with a Rails engine to share functionality between client projects and have gotten quite far with it. The engine contains controllers, models, views, and even routes. It provides core functions needed in each project (access to our in-house content management system) so projects don't have to start from scratch.

Most of the code has been structured in a way that it can be easily extended or overwritten where needed in the projects (mostly by subclassing). It's distributed as gem.

I can't show you code (it's not open-source), but I can point you to some helpful resources:

• Rails 3 Plugins - Part 1 - The Big Picture
• Rails 3 Plugins - Part 2 - Writing an Engine
• Rails::Engine documentation
• Plugin Authors: Toward a Better Future

Hope this helps!

Making copies is not always bad. That's why I ask about the reasons you don't want to copy the code.

If you create a 'library', you must ensure that every application will use it in the same manner. Or you have to prepare the 'library' for every possible difference between your applications which use it.

If you share the code, you are adding a dependency to your program. Any change in that shared code will affect more than one application.

Often it's much simpler to copy the code to another application, because then your may apply any modification without thinking about others.

Are you sure that managing users is so generic that you will not make any application-specific changes to it?

What about creating links to the files/directories that have the MVC? That is better than making copies.